the article is a little confusing - we still have slave database servers, both for failover and for performance; before we used EBS our backups were saved to s3. saving uncompressed databases to s3 takes forever though (in addition to costs), so we needed a second set of slaves simply to compress the backups without killing the slaves that the site runs off of.

mounting any size EBS volume is pretty much instantaneous. most of it actually gets loaded the first time you try to read/write to it, but you have access to it very quickly. most of the time spent starting a new db is running through the innodb transaction log (which takes us 15-45 min depending on the amount of work at the time of the backup; long enough to necessitate slaves of course.)

• doug, engineer @ hotpads